After being repulsed twice trying to take Fort Wagner by storm, Maj. Gen. Quincy Adams Gillmore decided on a less costly approach and began laying siege to the fort. In the days following the second battle of Fort Wagner. Union gunners made use of a new piece of artillery known as the Requa gun—25 rifle barrels mounted on a field carriage, while sappers dug zig-zag trenches toward Fort Wagner a second novelty was used—the calcium floodlight. The ground the Union sappers were digging through was shallow sand with a muddy base, the trenching efforts also began to accidentally uncover Union dead from the previous assaults on Fort Wagner. Disease and bad water plagued soldiers on both sides, the Union army maintained a constant rotation of soldiers to man the forward trenches of the grand guard. During the evening of August 16 a Confederate artillery shell burst through the serving as the headquarters for Colonel Joshua B. Howell, commanding officer of the guard that evening. A shell fragment struck Colonel Howell wounding him severely in the head, despite Howells quick recovery the incident prompted the Union commander to exclusively use veteran troops in the forward trenches. Confederates also kept a constant rotation of soldiers through Fort Wagner, during the night rowboats would bring fresh troops from the mainland to replace the garrison. Even though they had won a victory at Fort Wagner the Confederates fully expected the campaign to continue. Having a large garrison to draw from Gen. P. G. T, Beauregard was prepared to continue the campaign. Immediately in command of Confederate forces surrounding Charleston was former army officer. Ripleys forces were spread throughout fortifications surrounding Charleston Harbor and included a division of local South Carolina militia, Gilmore and Admiral John A. Dahlgren requested reinforcements from General-in-Chief Henry Halleck. Halleck was reluctant but nevertheless a division from the Army of the Potomac was transferred to the south under George H. Gordon, despite the marshy conditions on Morris Island, Union forces had constructed powerful batteries to combat Fort Wagner. These batteries were often named in honor of leaders such as Batteries Strong, Reynolds, Kearny. Others were named for high ranking officers such as Batteries Rosecrans. Inside Fort Wagner only one 10-inch Columbiad faced seaward and the few guns were in poor condition. During Colonel Lawrence M. Keitts tenure in command of the Confederate garrison he established stations on Fort Wagners west wall to coordinate with Confederate batteries on James Island
Image: FT Sumter East Barracks Sep 1863a
"Map of Charleston Harbor Showing Union and Rebel Batteries to September 1863." Period map drawn by Robert K. Sneden.